#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>
#include <sys/wait.h>
#include <stdlib.h>

void handler(int run)
{
    int status;
    int pid = waitpid(-1, &status, WNOHANG);
    if(WIFEXITED(status))
        printf("The child %d exit with code %d\n", pid, WEXITSTATUS(status));
}

int main()
{
    pid_t fork_pid;
    signal(SIGCHLD, handler);

    fork_pid = fork();

    if(fork_pid == 0)
        goto child_position;
    else
        goto parent_position;

    printf("nothing position\n");
parent_position:
    sleep(10);
    printf("this is parent! PID=%d\n", getpid());

    return 0;
child_position:
    printf("This is child! PID=%d\n", getpid());
    return 1;
}